Repeat probing was for many years the only method available for persistent obstruction. However, because the repeat probing procedure was associated with failures, surgeons began to probe the nasolacrimal duct and to place a temporary stent in the nasolacrimal duct. Nasolacrimal duct intubation has been an alternative to probing for relief of NLDO for more than thirty years. Most often, silicone tubes are left in the drainage system for 1 to 3 months to allow time for complete healing around the tubes resulting in canalization. The stent is removed with topical anesthesia. Conscious sedation or general anesthesia may be utilized at investigator discretion. The reported success proportions for nasolacrimal intubation following failed probing vary from 69% to 100% in published reports.